1. Field of the Invention
This invention relates to a display unit and in particular to a display unit using a scroll-like flexible medium which is writable and erasable at high speed and continuously displayable.
2. Description of the Related Art
Background display units include display units using liquid crystal used for applications from monochrome LCD of a watch, a camera, etc., to color LCD of a color TV, a personal computer, etc., LED used mainly for segment display, etc., and plasma enabling a large-sized and flat color display to be formed by discharge light emission.
However, with the background display units of liquid crystal, LED, plasma, etc., if power is turned off, display also all disappears, and the display operation of power reduction and storage holding type capable of holding display if power is turned off cannot be performed. Therefore, if an attempt is made to leave a display image, an image printing method on a printer, etc., is only available, thus paper is consumed each time printing is executed.
In recent years, displays capable of performing the display operation of storage holding type with a writable and erasable record medium by applying an electric field, heat, or magnetism have also been developed.
For example, a sheet-like electric field display is introduced as xe2x80x9cgyricon electric paperxe2x80x9d in journal xe2x80x9cSID 98 DIGESTxe2x80x9d p.1010 to p.1013. That is, it is a display 0.12 to 0.8 mm thick comprising dichroic spheres 25 to 100 m in diameter bonded between polyester sheets. An electric field (for example, 40 nanojoule/square centimeter) is applied to the space between the polyester sheets, whereby the dichroic spheres are rotated and are inverted in direction and the color appearing so far disappears and another color appears. After the sphere is once rotated, it is deposited on the wall face of the hollow storing the sphere, thus after the electric field is removed, the state is still maintained. That is, the record state is continuously displayed. An electric field is given reversely, whereby the record is erased.
A sheet-like heat display is introduced in, for example, xe2x80x9cDenshi jouhou tuushin gakkai gijyutu kenkyuu houkoku CPM83-18.xe2x80x9d That is, if external heat is applied to a heat medium for setting the temperature of the medium to a predetermined temperature or more, a color different from the initial color is presented; if the medium is cooled, the color is restored to the former color. For example, Ag2HgI4 is available as the material and the color becomes yellow at a predetermined temperature or less and becomes orange at the predetermined temperature or more. Ag2HgI4 is applied onto a transparent polyester film and this film and another transparent polyester film are placed to form a sandwich via an adhesive layer. Information is recorded with a thermal head, is held at normal temperature or by a heater, and is erased electronically with an electronic cooler using the Peltier effect. The display is placed on a row for line-sequential display or is placed like a plane for plane-sequential display.
A sheet-like magnetic display is also known. Using a magnetism phenomenon in which a magnet attracts iron powder, magnetic energy is given to a record medium through a record head, whereby magnetic powder (toner) is attracted. The magnetic powder is continuously attracted onto the record medium because of residual magnetism still after the magnetic energy is removed. For erasion, the residual magnetism is demagnetized by an erasion head. For example, xcex3-Fe2O3, Coxe2x80x94Nixe2x80x94P, CrO2, etc., is used as the magnetic powder material.
A display unit has been known wherein such continuously displayable record media under electric field control, heat control, or magnetism control are used to make up a display panel or are concatenated like a ring for forming endless paper and the display panel or endless paper is combined with a line head and wherein when information is changed, the head is driven at the same time as the endless medium rotates or the head moves, and new display contents are rewritten.
However, the display made up of such record media is like a panel or endless paper and lacks portability or practical utility.
It is therefore an object of the invention to provide a scroll-type display wherein by writing an image onto a scroll-like writable and erasable flexible medium using an electric or magnetic write head, high-speed image rewrite display is enabled on the flexible display medium, wherein the display operation of power reduction type is enabled so that display of the written image can be held if a drive source is removed, and wherein an image can be displayed in such a manner that the writable and erasable flexible display medium can be fed out from and inserted into a magazine like a scroll.
In this invention, there is provided a continuously displayable scroll-type display storing a writable and erasable and continuously displayable flexible medium like a scroll as display in a cylindrical magazine type case so that the flexible medium can be wound and/or rewound.
According to a favorable embodiment, the display displays the image based on an electrophoretic effect or magnetic-phoretic effect in the flexible medium.
According to further aspect, the flexible medium contains a mix layer of a particle containing a color substance and a fluid opaque medium.
According to another aspect, the flexible medium contains a mix layer of a particle containing a magnetic substance and a fluid opaque medium.
According to another feature, a display control section containing a CPU for controlling display of the flexible medium is placed in the cylindrical magazine type case.
According to the described configuration, the scroll-like flexible display medium is fed out from the magazine and an image is displayed, then it can be rewound into the magazine. A display is produced under the personal computer control and additional write and write are enabled according to personal computer information. An image can be written onto, erased from, and read from the scroll-like flexible display medium as desired. It is also made possible to communicate with an external computer. The surface of the flexible medium is traced with the additional write pen, whereby display can be added and erased.